Tire deflation indicator



Dec. 7, 1948. A. J. SCHULTZ TIRE DEFLATION INDICATOR Filed July 16, 1945 INVEN TOR ATTORNEY Patented Dec. 7, 1948 Anthony J. Schultz, St. Paul, Minn, assignor er one-half to Edward Crosby, St. PauL-Minm Application July '1 1945, Serial No; 605,3991

2 Claims. (01. 20058) This invention relates to an indicating system or signal device for automatically indicating to the driver of a vehicle when the pressure of one or more of the tires has decreased below a pre determined degree.

It is an object of my invention to provide a simple, efficient and inexpensive tire deflation indicator, which through lateral spreading of the lower portion of thetire upon the ground, when partially deflated, actuates a switch to close an electrical signal circuit.

Another object'is the provision of a simplified and accurate circuit controlling device for such a tire deflation indicating system which may be conveniently mounted upon the brake housing, axle or chassis frame of the motor vehicle and which may be very accurately adjusted to respend to lateral spreading or, the lower portion of the tire tread due to partial deflation.

More specifically, it is an object in a system and device of the class described, to provide a circuit controller utilizing a deformable and elastic element constructed of rubber or other suitable di-electric material properly disposed relative to the lower portion of the side wall of a tire for displacement and consequent closing of an electrical switch when the tire tread has been spread laterally beyond a predetermined limit due to partial deflation.

These and otherobjects and advantages of my invention will be more apparent from the following description made in connection with the accompanying drawings, wherein like refer: ence characters refer to thesameparts throughout the several views-and in which- Fig. 1 is a rear elevation of a portion of a truck supported on dual tires and having one form of my invention operatively applied thereto;

Fig. 2 is a rear elevationof the signal controlling device of Fig. 1, detached;

Fig. 3 is a cross section taken on the line-3-3 of Fig. 2 with the switch disposed in inoperative position;

Fig. 4 is a fragmentary rear elevation with Fig. 5 is a section taken on the line 5-5 of Fig. 4. I

Referring now to the form of my invention illustrated in Figs. 1 to 3 inclusive, I show the same operatively mountedon the stationary brake drum housing H of one of the rear wheels.

The truck on whichmy signalling or detector system is installed; is supportedupon dual tires T at the rear. 5

The circuit controlling-device. of my system, as shown in-Figs. 1 'to' 3 comprise-s an elongated depending arm B which. may conveniently be constructed from a strap of substantially rigid metal'and which'as shown, is hinged at its upper end to an attachment strap I provided with a pair of attachment apertures drilled therein for receiving suitable securing'means such as bolts 8. The hinge connection 9 between strap 1 and arm 6 as shown, comprises spaced overlapping ears at the respective longitudinal sides of the connected parts Which-are pivoted by transverse pin 9a. A torsion spring l0 surrounds the intermediate portion of pivot pin 9a and has one of its ends" fixed to the lower hinge member to urge said pivoted members into the position illustrated in Fig. 2. The device is secured to a suitable-stationary part of the automotive vehicle such as for example, the back of the brake housing, as shown in Fig. 1, by bolts 8 with the arms depending radially of the wheel a and substantially perpendicular to the ground.

To the lower end of arm 6, a substantially rigid bent metal strip II is secured by welding or rivetingsaid strip being bent to form an angled attachment-portion Ila, an outwardly extending medial portion 1 lb to which the movable or deformable element of the switch is secured and an angularly bent outer end I [0 which constitutes a relatively fixed contact for the electrical circuit. i I

A flexible and elastic'contact carrying shoe or arm l2 in the form of a relatively thick strip which may conveniently befconstructed from reinforced rubber or-any suitable material having flexing qualities with sufficient elasticity or resiliency to return to a predetermined position, is attached as shown, by rivets 12a to the medial and straight portion Nb of metal strip H. The outer portion or elastic shoe I'Z is free and is opposed tothe acutely angled outer end lie of the metal strip l I and its extremity is preferably tapered or rounded to facilitate bending of the free end when it is engaged by the revolving tire. The free portion of shoe l2 has, aflixed thereto and extending-transversely therethrough an electrical contact and terminal l3 having a contact disc 13a disposed at'the rear side thereof, normally spaced at short'distance from the for ward face of the metal stripiportion I to.

An adjustment screw i4 is provided in the upper end of dependingarm 6 having threaded seen that-a veryaccurate adjustment of the free end or tip of the contact carrying shoe l2 may be provided.

element such as a lamp bulb or buzzer S and with a battery B, depends from fthechassis'ofthe automotive vehicle and has itsend connected as shown in Figs. 1 and 3 with the terminal; I 3. The electrical circuit shown is of the grounded type, battery B being grounded to the metallic frame of the vehicle and connected with the electrical:-signallingselement S which in turn,- is connected with .wire: C. :1 The metal strip-.l'l is con-' nected by depending arm 6 with the brake drum housingx8 and throughthe housing, is. grounded toxthe frames. Thus, when movable contactelement [3a. carried by the. di-electric shoe [2,. is moved into engagement with thezacutely angled.

one of the rear tires is partially or totally deflated. Signal S is usually mounted on the instrument board or dash of the vehicle.

In Figs. 4 and 5, another form of my invention is illustrated which has in certain respects, superior advantages to the form first described.

The attachment strap and pivotal connection of the depending arm 6 of this second form is not illustrated as the sarneare identical with the form previously described. In this second form, a conductive tubular element It is welded or other- An electrical c ndu t or wir 3 hi h wise conductively secured to the lower end of connected in circuit with an electrical signalling rm fiend xtends u w r y and l t r l y in the direction of the opposed lower side wall portion of theyass'ociated tire .T.. A detachable di-electric and elastic nipple l'l is telescopically mounted over the medial andouter portion of tubular member l6 being constructed, 'as shown, of flexible 3 rubber or: other suitable material of flexible,

outer J'endof strip H, the circuit' is completed through groundil a In installing my apparatus,: the attachment strap .1 and pivotally connected arm 6 are dis-. posed substantially .radially .of the associatedv wheel and. preferably. perpendicularly. to the grounder. supportingsurface iorthe tire. :.'Ihe

lower .end :of arm G is preferablydisposed a few! inches above the ground linewithits out-turned conductive strip, extending-in. thedirec'tion of, i

theinner cheek of the; adjacent tire. Attachment... strap 1-; may then be. secured by suitable means;

such, as bolts18 whereafteradjustment screw l4 is manipulated to cause the extremity of the..d-i-. electricshoe l2 :to be disposed a short; distanced from thelower portion of the. tire trend. -To. ob--' tain :aprecise adjustment for a predetermined 1 partial inflation,;the, related. tire maybepartially. deflatedto the predetermined under-pressure and the adjustment screw on lock collar manipulated '1 to cause the tip of di-electric shoe I 2 .to abut.-

against the lower tread in" such. partially deflated...

condition. Thereafter, when the tires are again inflated to the normalgand desired pressure, the proper spaced relation ;;of shoe Hand, thetreads,

is obtained. In this connectiom. it will be. noted that the torsion spring l0 yieldingly retains arm:

6 in itsextreme-adjus ted position. z

,One of my deviOBs is supplied Ior each ofithe. rear wheels of the .automotivevehicle whether supported on dual orz slngle tires and' if desired, .l

devices ma a w esu lied or h rontwheels of the vehicle although this ,is not usually,

n ce sary" i .11. I.

In operation, when eitherofthe dual tires .T.

become partially deflated, a lateralbulging. occurs atthe lower portion of the tread of thetire dis. posed in juxt a-position to the .di-electric, shoe I2. 9

trical visual; 0.1 audible signal' and may. constitute ua il a i ih e li e, horn qfiba ov hi t mitates to t rate teat .Theclo sin g thisc ircuit operates aneleca flatted sidewvalljofthe lower portion of the associated tire. The outer portion of nipple l! as shown,- ,is solid, gandis axially ahdinternally apertured to receive ,and hold an electrical cont..me bs tl Showgir t m :o a screw or bolt which extendsnormally axially oi the metal tube lfiandisprovided with a contact head or annular flange 18a normallyspaced concentrically a very shortdistance from engagement with the inner. periphery-of the conductive tube It. A conductor orwire-Q, properlyinsulated, extends through an aperture in the lowerend of arm 6 and alsobthrough thegreater portion of conductiveltube l6 and has its end firmly connected in electrical contact with theendof contact bolt P8 carried'bythe nipple. I M I I In Figfj5', device .1ast describedis shown operated .by frictional engagement of a partially deflated tirejfwith' the nose lla of the di-electric nipple. Elexing-of the outenportion of nipple l1 due to} revolution. of thel associated tire, tilts the contactbolti l8"as1 shown,in Fig. 5, causing the fiang'ed' en'd or'headf lila to contact with the interior;.oIftheQconductive tube,-lB, thereby completing the circuitthrough the electrical signallingelenieht. In Fig. an; heavydotted line ini dicates, the engagingposition of the side wall of the assgoc iatedftire while the light-dotted line indicates the-normalposition of, the tire when inflated'to therequisite degree. k

Withtheiorm of my invention lastdescribed, it will be seen thatallparts ofthe electrical switch proper of my device; are completed encased and protectedjfrom. dust... moisture and grease. The

accuracy foith purposesmtenaea.

.t --P u r QF. Qd. h t va i changes may b' 'n'the iorm details are eme i and eraser-ti rs.sm le-pa i h ar n romihe stage. q'iinven i What is claimed is! p 1. tire.defl ees gna in a t a n inslj-a m ad e tab? s we tea v i e bslel fi l iiz tea e; 9f laiwhe l the ofiwitn its i emo rqs cl. 1 0th? side.- w lof a pneumatic We, a il ar o dutti em m ersec r d to the I we m r ian f setifibend arm d ing substantially perpendicular to the adjacent -t. iwa l 10 thaw ean he .emohjse eqami mcee n ient and deflectable free end adapted to be engaged by said side Wall when the associated tire is deflated below a predetermined pressure, said nipple internally carrying an axially disposed, electrical contact member, said member extending into said tubular member and being normally disposed concentrically and in spaced relation with the inner periphery of said tubular member.

2. In tire deflation signalling apparatus, a depending, substantially rigid arm adapted to be secured to a vehicle substantially radially of a wheel thereof with the lower end thereof opposed to the side wall of a pneumatic tire, a tubular, conductive member secured to the lower portion of said arm and extending laterally thereof and perpendicularly to the adjacent side wall of the associated tire, a rubber nipple attached to the outer end of said tubular member and disposed concentrically thereof and having a deflectible free end adapted to be engaged by said wall when the associated tire is deflated below a predetermined pressure, said nipple internally carrying 6 an axially disposed electrical contact member, said member extending into said tubular conductive member being normally disposed in spaced relation thereof, means for restraining said arm against oscillation axially of the associated wheel and threadedly adjustable means for varying the normal spaced relation of the lower end of said arm and the extermity of said nipple with respect to the adjacent side wall of the associated tire.

ANTHONY J. SCHULTZ.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,785,614 Boyer Dec. 16, 1930 1,883,040 Solve Oct. 18, 1932 2,144,187 Kotch Jan. 17, 1939 Certificate of Correction Patent No. 2,455,524. December 7, 1948.

ANTHONY J. SCHULTZ It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 20, claim 2, before the word wall insert side; column 6, line 3, same claim, before being insert and; line 8, same claim 2, for extermity read extremity;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of March, A. D. 1949.

THOMAS F. MURPHY,

Assistant Oommiasimwr of Patents.

Certificate of Correction Patent No. 2,455,524. December 7, 1948.

ANTHONY J. SCHULTZ It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 20, claim 2, before the word wall insert side; column 6, line 3, same claim, before being insert and; line 8, same claim 2, for extermity read extremity;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 29th day of March, A. D. 1949.

THOMAS F. MURPHY,

Assistant Oommiasimwr of Patents.

Certificate of Correction Patent No. 2,455,524. December 7, 1948.

ANTHONY J. SCHULTZ It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows:

Column 5, line 20, claim 2, before the Word Wall insert side; column 6, line 3, same claim, before being insert and; line 8, same claim 2, for extermity read extremity;

and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Offiee.

Signed and sealed this 29th day of March, A. D. 1949.

THOMAS F. MURPHY,

Assistant G'ommiasz'oner of Patents. 

